The first, is this interactive packing list I found on IndependentTraveler.com. It gives you a lengthy list of almost anything you might need on any kind of trip, then you select the ones you want and it puts all the items in a neat little printable list for you! I always use this when I go on a longer vacation, just to make sure I don't forget anything.
Personally, though, I like writing my lists by hand, so I can check off what I have, and colour-code the rest (laundry, to buy, last minute), and then when it gets too crowded, I can compile the leftover items into a new list!
As I check off items, I put them in different piles: Pants and shorts, Tops, Dresses, PJs and bigger items (Jacket, bathing suit bag, towel). Keep in mind, all of this is for almost a month of travelling with no laundry stops... (Minus the underwear, but who really wants to see that?)
Then, there's toiletries. I tend to always go a little overboard with those. I'm not a fan of travel-sized bottles, simply because I find that one shampoo bottle lasts about 4 days if I try really hard. And it's not always guaranteed there will be shampoo and soap in hostels, so I just bring Dollorama stuff that I can leave behind at the end of the trip. That way, I'm sure not to run out, and it's extra room I can use for souvenirs! And that orange bag at the back? That's a waterproof bag that I will be using to carry my toiletries in my bag so they don't leak, and also my valuables when I go take a shower!In case you were wondering, the Eucerin bottle is an after-sun lotion that I bought in Germany. It does miracles, and I will definitely need this in Thailand! Also, I always bring a Swiss Army knife with me. Those little guys are always useful! As are band-aids.. Especially with my track record of injuries...Of course, there are a few things missing in this pile, but those are just the last minute things I need to add the night before (i.e. Toothbrush) Question is, how do you keep your shampoo bottle that's too big for a Ziploc bag from leaking? Here's the answer! Just put a plastic bag between the cap and the bottle, then wrap the bag around the bottle!
One thing I also do, is that from the clothes I plan on bringing, I take out a comfortable outfit that I will wear on the plane, that way I'm not bringing any extra clothes, and it leaves more room in my bag (always bring a sweater, even in a tropical country. Airplanes are evil for their air conditioning and some nights can be pretty chilly).The last thing I do, is I stuff everything in my bag WITHOUT folding it. If it all fits without being properly folded, that means there will be lots of room on the way back when it will be neatly rolled and tucked in every tiny little empty space.And voila! That's how you pack light like a pro!